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Turbo Whoosh Noise on decelerating

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Old Jul 7th, 2018, 18:57   #1
sdg1970
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Default Turbo Whoosh Noise on decelerating

As above. Turbo is Standard 16T on a 97 V70r - Stage 1 remap that boosted well to 13psi+. Over the last couple of days, it's started boosting to around 8psi only and a fairly audible whooshing/rush of air noise is heard on deceleration. It never did that before and it doesn't do it on acceleration, oddly. Is this a faulty wastegate or dump valve and why would that cause a loss of around 5-6 psi of boost pressure?? 🤔 TIA
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Old Jul 7th, 2018, 19:48   #2
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Have you checked your vac lines? I had a pressure drop and a whoosh with a knackered vac line.
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Old Jul 7th, 2018, 21:54   #3
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Could be a split in your recirculation valve.
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Old Jul 7th, 2018, 22:26   #4
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Am checking it over Tuesday - just thought I'd get some opinions on what it might be!?? Where would I find the recirculation valve?? Never heard of that if Im honest...
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Old Jul 7th, 2018, 22:27   #5
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Quote:
Originally Posted by Cookeh View Post
Have you checked your vac lines? I had a pressure drop and a whoosh with a knackered vac line.
Which vac line and where?
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Old Jul 7th, 2018, 22:55   #6
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Am checking it over Tuesday - just thought I'd get some opinions on what it might be!?? Where would I find the recirculation valve?? Never heard of that if Im honest...
It's built into the turbo compressor housing, does a similar job to dump/blow off valves, it's not uncommon on these to fail. You can blank them off or replace it.
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Old Jul 7th, 2018, 23:17   #7
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Originally Posted by sdg1970 View Post
Which vac line and where?
Mine was wastegate actuator.

Have a watch of this for more info on vac lines.

https://www.youtube.com/watch?v=x8sXo5gbapM
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Old Jul 8th, 2018, 18:27   #8
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I had the same symptoms with a split recirc valve
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Old Jul 10th, 2018, 17:48   #9
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So it needs two vac pipes on the turbo side. A wastegate solenoid, turbo to airbox pipe and we think idle control valve. Possibly also a top intercooler hose. All in all an expensive day, but worth every penny to restore the fun factor. Thanks for all the help!!
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Old Jul 11th, 2018, 18:29   #10
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I've decided to replace the recirc valve diaphragm too, but I'm having trouble sourcing a new one for some reason. Is it Volvo only part?? Anyone got a link?? 🤔
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